Do I need to wait until a patent is granted before I start using my invention commercially?

This simple answer is no, you don’t need to wait for a patent to be granted before starting to use your invention publicly or commercially. However, using your invention publicly or commercially without first filing a provisional or non-provisional application could bar you from later filing an application. In short, once you have filed a patent application, you may use your invention commercially without barring your chances of obtaining a patent, as long as the application contains all the details of your invention. Once your application is filed, it is prudent to publicly mark your invention with PATENT PENDING.